COMMON WRITING MISTAKES

HOMOMPHONES: Word that sound the same, but have different spellings and meanings

EXAMPLE: their and there

go sit on the chair over there.

those bikes are theirs.

effect and affect

the medicine he took had a bad effect on him.

that movie had great affects.

who and whose

who are you?

The boy whose hair was tangled and matted.

APOSTROPHES:To creat forms, contractions and some plurals. The apostrophe shows where some letters have been left out of a contraction.

EXAMPLE: you are and you're

you are not going to be able to go out tonight.

you're going to get caught..

two children's hats.

two boys' hats

Sources

http://www.grammarbook.com/punctuation/apostro.asp

http://www.jjuriaan.com/Top_Ten_Common_Writing_Mistakes.htm